Two years ago, in the South Pacific, an explosive swarm of algae took over an area of water the size of Australia. This is often accompanied by land discharge, such as nutrient-rich farm waste flowing into the ocean. But in the middle of the sea, there is no farm?
As it turned out, the root cause of this phenomenon was a large forest fire that occurred thousands of kilometers west of the sea.
Australia’s bushfire disaster in 2019.
In new research published on Nature, the scientists concluded: smoke from the historic bushfires that took place in Australia in 2019 flew into the sea and provided nutrients to help the algae community thrive. The smoke rich in the elements iron and phosphorus has created an array of algae larger than the size of Australia itself.
“We know that fires have a devastating effect on local ecosystems,” said Nicolas Cassar, study co-author and professor of biochemistry at Duke University. But with the release of nutrients, the fire”It also affects ecosystems thousands of kilometers away from where the fire broke out“.
As wildfire season continues to ravage the western United States and the Mediterranean region, new research sheds light on our understanding of climate change-induced disasters, showing how extreme events How does it affect the Green Planet? Fire destroyed houses, took human lives, but huge forest fires changed the aquatic ecosystem with smoke floating in the air.
Satellite images show red smoke rising from Australia.
This is how smoke nourishes the sea
Most of the smoke generated from combustion is toxic to the body. Air pollution is also one of the pathogens that cause diseases and reduce human life expectancy.
But just because they’re toxic to humans doesn’t mean other organisms react the same way. Wildfire smoke contains nutrients such as iron and phosphorus, which can help algae and plants grow green, just like we fertilize trees to make them more lush.
Of the nutrients directly produced after forest fires, some will remain in the soil and some will fly with the smoke. That’s according to Douglas Hamilton, a researcher at Cornell University who specializes in how dewdrops affect the biogeochemistry of the ocean.
Air currents carry nutrients away.
In the case of the Australian bushfires, the air currents carried the smoke to the South Pacific, specifically an area of water with low iron concentrations. Here, any large source of iron can become a catalyst for algae growth.
The new report claims that the smoke from the forest fires has caused the algae community to grow rapidly, forming two large patches of algae (area highlighted in red in the image below). According to the authors, the growth rate of algae peaked in January 2020 and lasted about 4 months.
The number of seaweeds explodes in the areas highlighted in red.
This result is surprising because this time, the amount of algae in the studied waters is higher than the same period in previous years. Scientists have known for a long time that air currents are one of the sources of nutrients for organisms, but until now, they have not known about the impact of wildfires on the growth rate of algae. This is the reason why the new discovery is “groundbreaking”.
How are wildfires affecting the future of the ocean?
Climate change is making wildfires more destructive, but scientists still don’t know what effect they will have on the oceans in the future.
In the new report published in Nature, high fire can cause algae to thrive, but the local environment will also play a big role. If the medium is already nutrient-rich, large amounts of iron and phosphorus will not cause any bioburden.
Even when explosions occur, it is not clear whether their effects are good or bad. Plankton in the water with the same photosynthetic ability as plants can absorb CO2 from the air; i.e. the more algae, the lower the amount of greenhouse gases. That is why there are organizations that have raised the idea of pouring nutrients into the sea to stimulate algae growth.
One of the seaweed species appeared after a forest fire in the US in 2017.
However, the huge amount of algae does not necessarily absorb enough CO2 to offset the amount of greenhouse gases produced by forest fires. Besides some algae organisms that can permanently keep CO2 in the body, some algae also release CO2 into the environment when they decay.
“There is a good way to not rely on the amount of carbon that the plankton absorbs, which is to stop releasing CO2,” said researcher Hamilton.
Explosive algae events can also throw local ecosystems out of balance. Many times we have witnessed the mass death of fish due to algae. Algae can even produce “dead zones” where living things don’t have enough oxygen to grow. Worse, algae can have an adverse effect on the food chain.
The new study opens up more questions, such as how wildfires affect marine algae, and provides data that complicates already complex climate prediction models.
But while their influence is unknown, this is still valuable information that helps us better understand the very home of humanity, where we have lived and evolved for hundreds of thousands of years and still cannot comprehend.
According to Vox